1. Field of the Invention
The present invention is related to a voltage converter, and more particularly to a voltage converter for controlling a body forward bias voltage of a transistor.
2. Description of Related Art
Voltage converter is a voltage conversion circuit which utilizes an inductor to perform charging and discharging. The voltage converter not only has a boost converter structure but also has a buck converter and a buck/boost converter structure, and the voltage converter is one of most popular power supply devices.
FIG. 1 is a schematic diagram illustrating a conventional boost voltage converter. Referring to FIG. 1, in a boost voltage converter 100, a body terminal of a PMOS transistor 110 is connected to an output voltage Vout, and a body terminal of a NMOS transistor 120 is connected to ground terminal Gnd.
FIG. 2 is a schematic diagram illustrating a conventional buck voltage converter. Referring to FIG. 2, in a buck voltage converter 200, a body terminal of a PMOS transistor 210 is connected to an input voltage Vin, and a body terminal of a NMOS transistor 220 is connected to the ground terminal Gnd.
FIG. 3 is a schematic diagram illustrating a conventional buck/boost voltage converter. Referring to FIG. 3, in a buck voltage converter 300, body terminals of a PMOS transistor 310 and a PMOS transistor 330 are both connected to an input voltage Vin, and body terminals of a NMOS transistor 320 and a NMOS transistor 340 are both connected to the ground terminal Gnd.
As illustrated in the above-described FIG. 1˜FIG. 3, since the body terminal of each of the PMOS transistors is respectively connected to the input voltage Vin or the output voltage Vout (i.e., a highest voltage level), and the body terminals of each of the NMOS transistor are all connected to the ground terminal Gnd (i.e., a lowest voltage level). Therefore, the voltage converters 100˜300 are unable to adjust voltages on the body terminals of each of the transistors.